Thin film transistor liquid crystal displays are optoelectronic products which use thin film transistors as control elements and liquid crystal as medium and which integrates large-scale semiconductor integrated circuits and flat panel light source technologies. With such advantages as low power consumption, convenient portability, application of wide range, high quality and etc., thin film transistor liquid crystal displays become the dominant display products of a new generation.
A touch panel is adopted in the display device in order to allow a user to perform operations while viewing displayed pictures. A touch display screen is one of the important medium integrating an input terminal and an output terminal. With measure of the coordinate positions of touch points on the display screen, the intention of the person who touches the display screen can be obtained according to the displayed contents or patterns corresponding to the coordinate points on the display screen, whereby relevant operations are performed. At present, technologies of resistance type, capacitance type, infrared type, surface sound wave type, etc., are mainly utilized to realize determination of positions of touch points. Usually, touch screens embodying these technologies are separately manufactured first and then are attached to display screens, thus realizing touch control for the display screens. Such touch display screens formed by the touch screens and the display screens which are separately manufactured usually have higher costs and are of greater thickness and weight, which is not helpful to meet the requirements on thin and light display screens. Since the shift amount of overlapping is relatively great during the course of attachment, the touch control positions cannot be precisely located. Attachment of the touch screen to a surface of the display screen will lower the light transmittance of the display screen, and a backlight source with a higher power is required under the same conditions of display brightness.
Since the touch screen and the display screen are separately manufactured before they are assembled together by attachment, the touch display screens in the prior art have the problem that the functions of the touch panel and the display panel are not integrated.